1. Field of the Invention
The present invention relates to a device used to rigidfly a hitch for a vehicular tow trailer.
2. Description of the Prior Art
Hitches have long been used to provide a mechanism for connecting a trailer with a towing vehicle. Such hitches, especially when used to connect a trailer to a motor vehicle, are typically detachable from the towing vehicle.
Hitches are made detachable from the towing vehicle to solve the following dilemma. It is useful for hitches to extend beyond the rear of the towing vehicle to facilitate attachment of the trailer to the hitch, and to allow the trailer to pivot freely relative to the towing vehicle. This extension, however, can be awkward and dangerous when the vehicle is used without the trailer attached.
A hitch is commonly attached to the towing vehicle by means of a rigid rectangular sleeve which is mounted at the rear of the vehicle. A rectangular shaft of the hitch that is slightly smaller than the sleeve is inserted into the sleeve. A pin or bolt is then inserted through matching holes in the side walls of the sleeve and shaft, and then fastened to prevent the pin or bolt from slipping out of the holes.
Some space is usually left between the walls of the sleeve and the walls of the shaft to allow easy attachment and detachment of the hitch. For the same reason, space is usually left between the pin or bolt and the holes in the walls of the shaft and sleeve. These spaces are large enough to allow for ease of coupling and decoupling of the hitch despite imperfections in the machining of the hitch and sleeve and despite rust and other surface accumulations.
The problem with these spaces is that they allow play in the connection between the hitch and the sleeve that can be noisy, bothersome and dangerous. The play between the walls of the hitch and sleeve can cause clanging noises and vibrations that can be felt within the towing vehicle. That play may also be magnified by the lever arm of the hitch so that it is felt more strongly by the trailer. The play between the pin or bolt and the holes in the walls of the shaft and sleeve can be felt mainly in the acceleration and deceleration of the trailer relative to the towing vehicle. Both types of play can cause loosening of the bolt or pin fastening the hitch, which can, on rare occasion, result in detachment of the hitch and trailer, possibly while traveling at high speed. Both types of play can also increase wear and stress on various parts of the mechanisms attaching the trailer to the towing vehicle, leading to the ultimate failure of those parts.